The invention relates to a tin furnace component used to PCBA board soldering tin, in particular to a tin furnace kettle orifice. The kettle orifice has a rectangular shape, at least one tin overflow outlet is arranged on a long edge of the rectangle edges, the tin overflow outlet is a rectangular opening, the deepness is 2-8mm. The invention has a simple structure, can improve the soldering efficiency, is suitable for mass automatic production, in addition, effectively prevents an oxide layer of the tin liquid surface from remaining on the PCBA board, assures the welding joint quality.